It is common practice to-day to manufacture finger joint lumber as it reduces waste and provides a good product. As an example long lengths (40 feet or more) of 2″×4″ or 2″×3″ lumber are made by joining end-to-end a number of short lengths. The short lengths may vary in length from about 18 inches to about 7 feet. The long lengths (i.e. 40 feet or more) are then cut to exact lengths and which may for example be the length required for selected jobs. Wall studs for example in house construction are normally shorter than the conventional 8 foot length commonly available at a lumber yard. Each 8 foot length therefore must be cut at the job site resulting in considerable waste. Manufacturing to exact length not only reduces wastage at the job site but also eliminates a cutting step for the contractor. Also any left over pieces at the mill can be reprocessed.
During finger jointing each piece to be joined to another must have “V” notches cut in the ends thereof. This requires placing the pieces to be joined one stick at a time one after another on a conveyor that feeds the pieces to the finger jointing assembly line. An apparatus capable of receiving and holding numerous pieces to be finger jointed and then delivering therefrom one at a time (i.e. singulating) to the infeed end of the finger jointing assembly line speeds up the process and reduces the manual labor required.
U.S. Pat. No. 5,351,729, issued Oct. 4, 1994, Inventor Maurice J Brisson, discloses an apparatus for unscrambling and moving logs up an inclined path. The path has a direction transverse to the length of the logs and the logs rest in notches in vertically disposed, parallel, horizontally spaced apart, plates. In the patented apparatus the logs have to be longer than the spacing between the plates and thus is limited in that respect. First and second groups of such plates are reciprocated in an out of phase relation causing the logs to move one notch at a time. The two groups of plates are connected to a rigid support frame by link members. Some of the plates are interconnected by horizontal plates while others are not.
There is debris associated with log conveying that includes pieces of bark, chips and the like. In the above patented apparatus this debris falls between the vertically disposed plates dropping into the drive mechanism below or alternatively slides down a plate that joins together two adjacent plates and accumulates in hard to get at piles at the front of the apparatus.
Other patents on this subject are as follows:
Canadian Patents                2,319,330 Issued Feb. 12, 2002        2,271,931 Issued Dec. 28, 1999        2,270,484 Issued Oct. 17, 2000        2,105,219 Issued May 14, 1996 (corresponds to above mentioned U.S. Pat. No. 5,374,157)        2,074,645 Issued Aug. 29, 1995 (Corresponds to U.S. Pat. No. 5,351,729).        
The above Canadian Patent 2,319,330 discloses two groups of overlapping platforms that reciprocate along inclined paths in an out of phase relation. Each platform has a leading edge and when the leading edges of the two groups are closely adjacent an article on the face of one platform in one group transfers to the face of a platform in the other group.
The forgoing references disclose the use of link arms to mount the movable assemblies on the support structure—see 2,074,646 and 2,105,219 or linear slide bearings—see 2,270,484, 2,271,931 and 2,319,330. The latter patent also discloses having the platforms sufficiently close as to be capable of moving debris along with the articles.
The forgoing references are not concerned with singulating pieces of lumber.
Lumber pieces are rectangular and of specific dimensions and therefor they need special consideration not applicable to unscrambling and handling of round logs.
Also the prior art is not concerned with the infeed to the apparatus nor details of construction of the infeed end of the apparatus.
In the patented apparatus the depth of the leading edge of each is of the same.